Firmware update for consumer electronic device

ABSTRACT

To update firmware on a consumer device intelligently, two or more application images are stored as firmware on the consumer device. If the primary application image is corrupt, the back-up application image is executed on the consumer device. The back-up application image can be updated based on the primary application image. User configuration files can be preserved during the update of an application image, or they can be overwritten. This firmware updating scheme can be advantageously implemented in a personal media broadcasting system.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.60/696,096, filed Jun. 30, 2005, which is incorporated by reference inits entirety.

BACKGROUND

This invention relates generally to consumer devices having one or moreprocessors, and, more specifically, to updating and loading the firmwarestored on such devices.

A number of consumer grade devices that run embedded software have theability to accept firmware updates that allow the end user to usefeature enhancements and to address problem fixes. These updates areoften initiated by the user and are typically critical in nature.Failures in the update process are often catastrophic.

A failure could be due to power failure or glitches on the embeddeddevice and/or the host initiating the update. Failures may also resultfrom network interruptions and any number of other problems. When afailure occurs, the firmware on the consumer device is often erased orotherwise corrupted. Because firmware is typically integral to thesuccessful operation of the device, the corruption or loss of thefirmware can cause the consumer device to perform improperly, and insome cases, to be completely inoperable. Perhaps worst of all, once thedevice has been rendered inoperable, it may be impossible or impracticalto restore the firmware. Thus, a failure during a firmware upgrade canresult in the loss of the consumer device.

Therefore, what is needed is a way to intelligently update the firmwareof a consumer device.

SUMMARY OF THE INVENTION

To avoid the problems in previous consumer devices, embodiments of theinvention intelligently update the firmware of a consumer device. Aback-up application image is stored as firmware on the consumer device.If the primary application image is corrupted, the back-up applicationimage can be executed instead, maintaining at least some of thefunctionality of the consumer device.

In one embodiment, two or more application images are stored as firmwareon the consumer device. A processor executes the first applicationimage. A determination is made as to whether the first application imageis corrupt. If the first application image is determined to be corrupt,the processor executes the second application image. By executing thesecond application image as a back-up, the consumer device is ableoperate as normal even if the first application image is corrupt. Theconsumer device may also initiate an update to repair the corruptedapplication image. Because user configuration files are storedindependently of application images, the update can repair the corruptedapplication image without overwriting user configuration files.

Furthermore, so that the back-up firmware can provide greaterfunctionality, embodiments of the invention update the back-upapplication image. A processor executes a primary application imagestored as firmware on the consumer device. The first application imageis updated with an updated application image. If the updated applicationimage is determined to be not corrupt, the updated application image isused to update the back-up application image, which is stored asfirmware on the consumer device. The back-up application image isavailable in case the primary image is subsequently corrupted. In thisway, the back-up application image can be safely updated while reducingthe likelihood of corrupting the back-up image. By updating the back-upapplication image, a back-up copy of firmware can be kept up to datewith non-corrupt application images.

The first application image can be determined to be corrupt using avariety of methods. According to one embodiment, the first applicationimage can be determined to be corrupt by reading one or more flags todetermine if an update was initiated but not completed. An incompletelyupdated application image is determined to be corrupt. According toanother embodiment, a checksum is used to determine if an applicationimage is corrupt.

The features and advantages described in this summary and the followingdetailed description are not all-inclusive. Many additional features andadvantages will be apparent to one of ordinary skill in the art in viewof the drawings, specification, and claims hereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating a consumer device, according toone embodiment of the present invention.

FIG. 2 is a state diagram illustrating the execution of a plurality ofapplication images, according to one embodiment of the presentinvention.

FIG. 3 is a flow chart illustrating a method for updating an applicationimage, according to one embodiment of the present invention.

FIG. 4 is a flow chart illustrating a method for loading an applicationimage, according to one embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In one embodiment of the present invention, a back-up application imageis stored locally in a consumer device. If the primary application imageis corrupted (for example, due to an update failure or a data loss), theback-up application image can be executed instead, maintaining at leastsome of the functionality of the consumer device. During the executionof the back-up application image, the primary application image can berestored. Storing two application images in the consumer devicebeneficially increases the failure resistance and reliability of theconsumer device.

In one embodiment, the consumer device is a personal media broadcaster,such as the one described in U.S. application Ser. No. 11/147,664,entitled “Personal Media Broadcasting System,” filed Jun. 7, 2005, whichis incorporated by reference in its entirety. An application image for apersonal media broadcaster may include processor instructions causingthe media broadcaster to encode a video source and stream it over alocal or remote network to a media player. Storing two or moreapplication images as firmware on a personal media broadcaster isparticularly beneficial given the typically challenging operatingconditions of personal media broadcasters. Personal media broadcastersare often power-cycled without warning, have unreliable connections tothe Internet, and are frequently moved, resulting in a high risk offirmware corruption. Furthermore, users often expect that, with minimaluser intervention, their personal media broadcasters be up-to-date withcontinuously improved firmware. The intelligent firmware updatedescribed herein advantageously provides reliable firmware updates for apersonal media broadcaster operating under even the most challenging ofconditions.

FIG. 1 is a block diagram illustrating a consumer device, according toone embodiment of the present invention. The consumer device 100contains a non-volatile memory 102, a volatile memory 101, a processor106, and at least one interface for receiving firmware updates. Forexample, the consumer device 100 illustrated in the figure includes anetwork interface 110 and a controller interface 108. The networkinterface 110 can be implemented, for example, as an Ethernet card, an801.11-compliant wireless device, a modem, a cellular modem, or anotherinterface capable of sending and receiving data on a network. Othercomponents not illustrated can also be included in the consumer device100.

The volatile memory 101 can be implemented as any kind ofcomputer-readable medium. The volatile memory 101 can be implemented,for example, by dynamic or static random access memory. The volatilememory 101 is capable of storing data and processor instructions for theprocessor 106. Typically, the volatile memory 101 is designed so that itwill lose its contents if power to the volatile memory 101 isdisconnected, but it need not be.

The non-volatile memory 102 can be implemented as any kind ofcomputer-readable medium that retains its contents when power to thenon-volatile memory 102 is disconnected. The non-volatile memory 102 canbe implemented, for example, by a disk drive, flash memory, ElectricallyErasable Programmable Read-Only Memory (EEPROM), or magnetic, OvonicUnified, or ferroelectric random access memory. Although thenon-volatile memory 102 is illustrated as a single component, thenon-volatile memory 102 can be implemented as any number ofcomputer-readable media. When reference is made herein to distinctnon-volatile memories, it should be understood that in one embodimentthese distinct non-volatile memories are implemented as distinctlocations within the same non-volatile memory. In another embodiment,distinct non-volatile memories are implemented as physically separatecomponents of the consumer device 100.

The non-volatile memory 102 stores processor instructions executable bythe processor 106. A group of computer instructions is typicallyorganized into a functional program called an application image 104. Anapplication image 104 (sometimes called a “binary image”) is a set ofprocessor instructions that, when executed by the processor 106, willcause the consumer device 100 to have its intended functionality.Because the application image 104 is stored embedded in the consumerdevice 100, the application image 104 is often referred to as“firmware.”

The non-volatile memory 102 includes two or more application images,such as application image 104A and application image 104B. Applicationimage 104A and application image 104B are independent and distinctgroups of processor instructions. When executed on the processor 106,either application image 104 will allow the consumer device 100 toperform its intended functionality without relying on the other(provided the application image is not corrupt).

The application images 104A and 104B can be identicalinstruction-for-instruction, or they can be different. For example,application image 104A can be an updated version of the applicationimage 104B, implementing additional functionality of which theapplication image 104B is not capable. As another example, applicationimage 104A can be corrupt, and application image 104B can be notcorrupt.

According to one embodiment of the present invention, the applicationimage 104A is stored on a first non-volatile memory and the applicationimage 104B is stored on a second non-volatile memory. The firstnon-volatile memory and the second non-volatile memory can beimplemented, for example, as separate locations on a single component ofnon-volatile memory 102. As another example, the first non-volatilememory and the second non-volatile memory can be implemented as distinctcomponents of non-volatile memory. In FIG. 1, the first and secondnon-volatile memories are implemented in a single physical non-volatilememory 102.

The non-volatile memory 102 may also contain one or more userconfiguration files 105. A user configuration file 105 comprises datastored on a computer-readable medium that indicates user preferences forthe operation of the consumer device 100. According to one embodiment ofthe present invention, the memory 102 contains two or more userconfiguration files 105A and 105B, each configuration file 105associated with an application image 104. While an application image 104is executing on the processor, the user configuration file 105associated with that application image 104 is considered the active userconfiguration file for the consumer device 100.

According to one embodiment of the present invention, the non-volatilememory 102 contains one or more flags 103 indicating whether an updateof the application image 104A has been initiated and whether the updateof the application image 104A was completed. Additional flags can alsobe implemented to indicate the update or corruption status of otherapplication images, configuration files, and so on.

According to one embodiment of the present invention, the non-volatilememory 102 contains a bootloader 107. The bootloader 107 is a set ofprocessor instructions for initializing the consumer device 100 andbeginning the execution of one of the application images 104.

The volatile memory 101 and the non-volatile memory 102 have beenillustrated as separate components for the purpose of illustration, butvarious embodiments of the invention are not limited to such aconfiguration. In one embodiment, the data structures described as beingstored on the volatile memory 101 and the data structures described asbeing stored on the non-volatile memory 102 are stored on a commonmemory. Furthermore, the examples of volatile and non-volatile memoriesdescribed herein are given for the purposes of illustration and are notlimiting. Other examples of volatile and non-volatile memory will beapparent to one of skill in the art without departing from the scope ofthe present invention.

FIG. 2 is a state diagram illustrating the execution of a plurality ofapplication images, according to one embodiment of the presentinvention. The consumer device 100 begins in a powered down state 202.When the consumer device 100 is in the powered down state 202, theprocessor 106 does not execute processor instructions. In someembodiments, data stored on the volatile memory 101 is lost when theconsumer device 100 is in the powered down state 202.

Power on brings the consumer device 100 to an executing bootloader state204. In the executing bootloader state 204, the consumer device 100initializes and determines which application image 104 to load. In oneembodiment, the application image 104A serves as a primary applicationimage, and the application image 104B serves as a back-up applicationimage, available for execution if the application image 104A isdetermined to be corrupt. Under normal conditions, the applicationimages 104A is selected. If the application image 104A is determined 204to be corrupt, the application image 104B is selected instead.

According to one embodiment of the present invention, in the executingbootloader state 204 the consumer device 100 copies the selectedapplication image 104 from the non-volatile memory 102 to the volatilememory 101.

If the application image 104A is determined to be not corrupt, theconsumer device 100 enters the executing application image 104A state206. The processor instructions of application image 104A are executedby the processor. In state 206, the user configuration file associatedwith either the application image 104A is used as the active userconfiguration file.

If the application image 104A is determined to be corrupt, the consumerdevice 100 enters the executing application image 104B state 208. Theprocessor instructions of application image 104B are executed by theprocessor. In state 208, the user configuration file associated witheither the application image 104A or the application image 104B is usedas the active user configuration file, according to various embodiments.According to one embodiment of the present invention, in state 208 theconsumer device 100 determines if the user configuration file associatedwith application image 104A is corrupt. If the user configuration fileassociated with application image 104A is not corrupt, it is the activeuser configuration file. If the user configuration file associated withapplication image 104A is corrupt, another user configuration file isthe active user configuration file.

A command to update the firmware causes the consumer device 100 to enterthe running update state 210. In state 210, the consumer device 100receives an updated application image 114 and stores the updatedapplication image in the non-volatile memory 102. The successfulcompletion of the update returns the consumer device 100 to theexecuting application image state. According to one embodiment of thepresent invention, at the successful completion of the update, theconsumer device 100 restarts, causing the consumer device 100 to returnto the powered down state 202.

Power-cycling the consumer device 100 during any state restarts theconsumer device 100 and causes the consumer device 100 to return thepowered down state 202. For example, if power is inadvertently removedin the running update state 208B, the consumer device 100 returns to thepowered down state 202, even though the update of the application image104 might not be complete.

FIG. 3 is a flow chart illustrating a method for updating an applicationimage, according to one embodiment of the present invention. An updatedapplication image is used to update the primary application image.

Updated application images can be obtained from a variety of sources,either local or remote. Typically, an application image 114 for updateis stored on a computer readable medium 112 external to the consumerdevice 100. The consumer device 100 can access the computer readablemedium 112 through the network interface 110 (for example, to access anapplication image stored on a local or remote server), the controllerinterface 108 (for example, to access a disk drive or USB port) or anyother suitable mechanism. Various methods for obtaining an applicationimage 114 for update will be apparent to one of skill in the art withoutdeparting from the scope of the present invention. Typically, updatingthe application image 104A includes copying the application image 114 tothe non-volatile memory 102 storing the application image 104A or 104B.

An update of an application image can be initiated, for example, by alocal or remote user command, or it can be initiated automatically inresponse to determining that the application image is corrupt, or inresponse to determining that an updated application image is available.For the purposes of illustration, the method is described for updatingthe application image 104A, but according to various embodiments, themethod can also be used to update other application images 104 stored asfirmware on the consumer device 100. According to one embodiment of thepresent invention, the update is performed by the consumer device 100.

The consumer device 100 optionally sets 302 a flag indicating that anupdate of the application image has been initiated. According to oneembodiment of the present invention, a flag is used to indicate that anapplication image update has been initiated and/or completed. If theupdate process is interrupted or for any reason does not complete, theflag will reflect the interruption and facilitate determining that theapplication image 104A is corrupt.

The consumer device 100 updates 304 the application image 104A.According to one embodiment of the present invention, updating 304 theapplication image 104A includes modifying or replacing the processorinstructions of the application image 104A with processor instructionsof an application image 114 stored on a computer readable medium 112external to the consumer device 100. For example, using a local ornetwork connection, the consumer device 100 can copy the applicationimage 114 to the non-volatile memory 102 that previously stored theapplication image 104A. The non-volatile memory 102 that previouslystored the application image 104A now stores an updated applicationimage. According to one embodiment of the present invention, theconsumer device 100 copies the application image 114 to the non-volatilememory 102 in 64-kilobyte segments and verifies that each segment wascopied correctly into the non-volatile memory 102 before proceeding tothe next segment.

According to one embodiment of the present invention, updating 304 theapplication image 104A includes copying the application image 104B tothe non-volatile memory 102 that previously stored the application image104A. The non-volatile memory 102 that previously stored the applicationimage 104A now stores a recovered application image. Such a recovery canbe useful, for example, if the user would like to return the consumerdevice 100 to a previous firmware version, or to standard factorysettings. According to one embodiment of the present invention, the usercan initiate a “hard reset” update that will copy the application image104B to the non-volatile memory 102 that previously stored theapplication image 104A. Hard resets can be initiated, for example, by asoftware command, by a hardware button on the consumer device 100, orboth.

Updating 304 the application image 104A can include overwriting the userconfiguration file associated with the application image 104A, or it canpreserve the user configuration file. Preserving the user configurationfile beneficially allows a user to enjoy the functionality of theconsumer device 100 without reconfiguration.

The consumer device 100 optionally sets 306 a flag indicating that anupdate of the application image is complete. According to one embodimentof the present invention, a flag is used to indicate that an applicationimage update has been initiated and/or completed. Setting 306 the flagindicating that the update is complete beneficially facilitatesdetermining that the updated application image is not corrupt.

The consumer device 100 loads 308 an application image 104 from thenon-volatile memory 102. For example, the consumer device 100 canrestart and load an application image 104 as in a typical start-upevent. A method for loading an application image 104, according to oneembodiment of the present invention, is described herein with referenceto FIG. 4. In one embodiment, loading 308 an application image includesdetermining if the application image 104A is corrupt. If the applicationimage 104A is determined to be corrupt, the consumer device 100 canautomatically restart the update of the application image 104A.

The consumer device 100 optionally updates 310 application image 104B.According to one embodiment of the present invention, certainapplication image updates can be designated as capstone updates whichupdate both a primary application image and a back-up application image.Updating 310 application image 104B can include setting a flagindicating that an update of application image 104B has been initiated,copying the updated application image to the non-volatile memory 102previously storing application image 104B, and setting a flag indicatingthat an update of the application image 104B is complete. Updatingapplication image 104B can further include associating application image104B with an updated user configuration file, such as the userconfiguration file previously associated with application image 104A.

Updating 310 application image 104B beneficially adds features andimprovements to the back-up application image, so that the functionalityof the consumer device 100 when the back-up application image is loadedwill be similar to the functionality when the updated application imageis loaded. Furthermore, by updating 310 application image 104B afterapplication image 104A has been successfully updated and loaded,corruption of the application image 104B can be avoided, increasing thereliability of the consumer device 100.

FIG. 4 is a flow chart illustrating a method for loading an applicationimage, according to one embodiment of the present invention. Theconsumer device 100 loads an application image as part of the start-upprocess.

Upon a start-up event, such as a power cycle or a restart, the processor106 executes the processor instructions of the bootloader 107. Theprocessor instructions of the bootloader 107 cause the consumer device100 to load an application image 104 and begin executing the processorinstructions of the loaded application image 104.

The consumer device 100 determines 402 if the application image 104A iscorrupt. According to one embodiment of the present invention, theconsumer device 100 determines 402 if the application image 104A iscorrupt by determining a checksum of the first application image 104A.If the checksum does not match an expected value, the application image104A is determined 402 to be corrupt. According to another embodiment ofthe present invention, the consumer device 100 determines if theapplication image 104A is corrupt by reading a flag to determine if anupdate of the application image 104A has been initiated. If reading theflag indicates that the application image 104A has been initiated, butnot completed, the application image 104A is determined 402 to becorrupt. According to yet another embodiment of the present invention,the determination 402 can include a combination of reading a flag todetermine if an update of the application image 104A has been initiatedand determining a checksum. These examples of methods for determining ifthe application image 104A is corrupt are given for the purposes ofillustration only and are not limiting. Other examples of method fordetermining 402 if the application image 104A is corrupt will beapparent to one of skill in the art without departing from the scope ofthe present invention.

If the consumer device 100 determines 402 that the application image104A is not corrupt, the consumer device 100 loads 404 application image104A. According to one embodiment of the present invention, loading 404application image 104A includes copying application image 104A from afirst non-volatile memory 102 to a volatile memory 101. The processor106 begins executing the processor instructions of application image104A. Loading and executing a non-corrupt application image 104Abeneficially allows the consumer device 100 to operate with a primaryfirmware image, providing the functionality and reliability to which theuser is accustomed.

If the consumer device 100 determines 402 that the application image104A is corrupt, the consumer device 100 loads 406 the application image104B. For example, the consumer device 100 can load 406 the applicationimage 104B by copying the image 104B to the volatile memory 101. Asanother example, the consumer device 100 can load 406 the applicationimage 104B by copying the image 104B to the volatile memory 101 and tothe non-volatile memory 102 that previously stored application image104A. The processor 106 begins executing the processor instructions ofapplication image 104B.

Loading and executing application image 104B beneficially allows theconsumer device 100 to operate with its intended functionality, evenwhen application image 104A is corrupt. In some cases such as when theapplication image 104A is a more recent firmware version than theapplication image 104B, certain advanced functionality may be reduced ormodified during the execution of the application image 104B.

According to one embodiment of the present invention, the consumerdevice 100 updates 408 application image 104A. If the application image104A is determined 402 to be corrupt, the consumer device 100 initiatesan update to repair the application image 104A. The update of theapplication image 104A can start automatically, or a message can bepresented to a user indicating that the primary application image iscorrupt and prompting the user for a command to initiate an update.

According to one embodiment of the present invention, an update of anapplication image can operate in at least two modes, one that willpreserve the user configuration file associated with application image104A, and another that will overwrite the user configuration file.According to one embodiment of the present invention, the consumerdevice 100 determines whether the user configuration file should beoverwritten. For example, if the consumer device 100 is updating theapplication image 104A in response to determining that the applicationimage 104A is corrupt, the user configuration file would not beoverwritten. As another example, if the consumer device 100 is updatingthe application image 104A in response to a user-initiated hard-reset,the user configuration file would be overwritten, for example, with theuser configuration file associated with application image 104B. Updatingthe user configuration file advantageously allows user preferences to bereset to previous or default settings, enabling the consumer device 100to recover from potentially inoperable user settings.

In the figure and accompanying description, reference is made toperforming various actions, such as determining corruption, loading, andupdating, on application images. For the purpose of illustration, suchactions are discussed with reference to application images 104A and104B. However, according to various embodiments, the steps describedherein can also be performed on other application images. For example,the method described herein with reference to FIG. 4 can also beperformed on updated and/or recovered application images.

Where reference is made herein to a primary embodiment containing twodistinct application images 104, this discussion has been provided forthe purposes of illustration and is not limiting. One of skill in theart will appreciate that further benefits are achieved by storing morethan two distinct application images 104 in the consumer device 100.Such benefits include, but are not limited to, further increased failureresistance, user selection of a plurality of firmware versions, andredundant application image back-up. The methods and systems describedherein can also be modified to implement embodiments with more than twoapplication images, as will be will be apparent to one of skill in theart without departing from the scope of the present invention.

The foregoing description of the embodiments of the invention has beenpresented for the purpose of illustration; it is not intended to beexhaustive or to limit the invention to the precise forms disclosed.Persons skilled in the relevant art can appreciate that manymodifications and variations are possible in light of the aboveteachings. It is therefore intended that the scope of the invention belimited not by this detailed description, but rather by the claimsappended hereto.

1. A method to operate a consumer device having a processor, the methodcomprising: initially creating user configuration data that maintainsuser-selected preferences for the operation of the consumer device whilethe processor executes a first application image; updating the firstapplication. image with a second application image; determining if theupdating of the first application image was successful; and if theupdating of the first image was successful, preserving the user-selectedpreferences contained in the user configuration data for continued useduring subsequent operation of the consumer device while the processorexecutes the second application image; and if the updating of the firstimage was not successful, resetting the user configuration data andcontinuing to use the first application image during subsequentoperation of the consumer device.
 2. The method of claim 1 wherein theresetting comprises restoring default settings for the userconfiguration data.
 3. The method of claim 1 wherein the resettingcomprises obtaining new user configuration data from the user.
 4. Themethod of claim 1 wherein the updating comprises simultaneously storingthe first application image and the second application image on theconsumer device and selecting one of the first and the secondapplication images to execute on the processor, wherein the selectingcomprises: determining if the second application image is corrupt;executing the second application image on the processor if the secondapplication image is not corrupt: and executing the first applicationimage on the processor if the second application image is corrupt. 5.The method of claim 1, wherein the updating comprises setting a flagindicating that an update of the first application image has beeninitiated and storing the flag in a memory of the consumer device. 6.The method of claim 5, wherein the determining comprises reading theflag to determine if an update of the first application image wasinitiated but not completed.
 7. The method of claim 5, wherein thedetermining comprises verifying a checksum of the second applicationimage.
 8. A method to operate a placeshifting device having a processorand a network interface, the method comprising: while the processor isexecuting a first application image, creating and storing userconfiguration data that describes user-selected preferences for theoperation of the placeshifting device; downloading a second applicationimage via the network interface; determining if the downloading of thesecond application image was successful; and if the downloading of thesecond image was successful, preserving the user-selected preferencescontained in the user configuration data for continued use duringsubsequent operation using the second application image; and if thedownloading of the second image was not successful, resetting the userconfiguration data and continuing to operate the placeshifting deviceusing the first application image.
 9. The method of claim 8 furthercomprising resetting the user configuration data when the user performsa hard reset of the placeshifting device.
 10. The method of claim 8wherein the placeshifting device processes television programming, andwherein the user configuration data comprises an indication of thetelevision programming that is available to the placeshifting device.11. The method of claim 8 wherein the user configuration data comprisesnetwork configuration information that allows the placeshifting deviceto communicate using the network interface.
 12. The method of claim 8wherein the user configuration data indicates user interface parametersfor providing user inputs to the placeshifting device.
 13. The method ofclaim 8 further comprising resetting the user configuration data anddownloading the second image in response to a user-initiated hard resetof the placeshifting device.
 14. A consumer device comprising: aprocessor; a network interface to the network; and a memory, said memoryconfigured to store a first application image, user configuration data,and a bootloader; wherein the user configuration data maintainspreferences for the operation of the consumer device based upon userinputs received while the first application image was executing on theprocessor; and wherein the bootloader is configured to download a secondapplication image via the network interface to the memory, to determineif the download of the second application image was successful, todirect the processor to continue using the user configuration dataduring subsequent operation of the second application image if thedownload was successful, and to direct the processor to reset the userconfiguration data and to continue using the first application image ifthe download was not successful.
 15. The system of claim 14 wherein thememory comprises a first non-volatile portion configured to store thefirst application image and a second non-volatile portion configured tostore the second application image.
 16. The system of claim 15 whereinthe memory further comprises a volatile portion configured to store acopy of one of the first and the second application images for executionby the processor.
 17. The system of claim 16 wherein the bootloader isfurther configured to determine which of the first and the secondapplication images to copy to the volatile portion of the memory. 18.The system of claim 16 wherein the bootloader is further configured todetermine if the second application image is corrupt, to copy the secondapplication image to the volatile portion of the memory if the secondapplication image is not corrupt, and to copy the first applicationimage to the volatile portion of the memory if the second applicationimage is corrupt.
 19. The method of claim 14, wherein the bootloader isfurther configured to determine if the download was successful bychecking a flag in the memory that indicates that the download wasinitiated but not completed.
 20. The method of claim 14, wherein thebootloader is further configured to determine if the download wassuccessful by verifying a checksum of the second application image.